1. Field of the Invention
This invention generally relates to closures for packaging containers and more particularly, to a removable lid for a cylindrical container, such as a round ice cream carton or the like.
2. Description of the Prior Art
In the past, removable lids for cylindrical cartons used for packaging ice cream or the like have been formed from paper stock and are often of a two piece construction. One piece of the lid was formed from a strip of material folded in a manner to provide a rolled edge and a pair of essentially straight, parallel, spaced apart annular shaped side walls. When installed on the carton, the rolled edge of the lid engaged the upper rim of the carton while the side walls of the lid were respectively disposed on the inner and outer surface of the carton rim. The second piece of the lid consisted of a circularly shaped piece of paper stock having the periphery thereof provided with extensions suitable for attachment, as by gluing, to the inner side wall of the first mentioned piece of the lid. The second circular piece of the lid was normally preprinted with various indicia to identify the manufacturer or contents of the carton, prior to assembly of the separate pieces of the lid.
Others in the past have also devised a one piece lid formed from paper stock, which is similar in construction design to the lid mentioned above and is provided with side walls forming a ring-shaped opening within which the rim of the carton is slidably received.
Prior art lids of the types described above are less than completely desirable for several reasons. First, the fit between the side walls of the lid and the carton rim was relatively loose unless sufficient friction could be produced between the side walls of the lid and the rim; this was sometimes achieved by spacing the side walls a distance marginally less than the thickness of the rim and/or extending the width of the lid side walls to create additional friction producing surface areas. Reduction of the spacing between the lid side walls naturally made it more difficult for a user to guide and start the carton rim into the opening between the side walls of the lid, and the provision of wider lid side walls necessitated the use of additional stock material, thereby diminishing manufacturing economy. In the case of a two piece paper stock lid construction, the additional labor costs associated with assembly thereof was also undesirable from the standpoint of economy. Finally, the necessity for preprinting the face of the lid, prior to assembly thereof added further undesirable manufacturing costs to this type of lid and also posed logistical problems since such lids could not be assembled and installed on the cartons prior to the application of the necessary printed indicia. Also, once these prior art lids were installed on the cartons, it was sometimes difficult to remove the lids since the outer side walls of the lid was, by necessity, closely contoured to the outer surface areas of the carton, making it difficult to apply upwardly directed pressure on the free extremity of the lid side wall.
Finally, because of the close proximity of the lid to the side walls of the carton, the ice cream in the carton, when removed from a refrigerator, would have a tendency to thaw, and when replaced in the refrigerator would expand, often popping the lid from the carton rim.
From the foregoing, it is clear that a need exists in the art for a circular lid for closing the end of a cylindrically shaped carton which is not only economical from a manufacturing standpoint, but easy to install and remove from the carton and allows the application thereto of a label having preprinted indicia thereon. Further, such a carton lid should be capable of being tightly adhered to seal the carton and provide the requisite closure therefore under all a conditions of use of the carton.